It is well known that networking technology was mastered by a relatively fe technicians and mainly served for political, military and other limited purposes during its initial development period of 1950's and 1960's. However, since then, with the rapid development of computer technologies, the appearance of personal computers, the emergence and prevalence of TCP/IP protocol, and the birth of the Internet, network technologies quickly evolved and were been put into widespread business use. Commercial uses of the Internet have developed at unprecedented speed and have penetrated various social sectors such as the government, medical and educational agencies. The Internet plays an indispensable role in many peoples' daily life.
IM or Instant Messaging, since its general introduction in 1996, has quickly become quite popular. IM began with ICQ software and is characterized by performing real-time communication via a network. IM may already be the most frequently used type of network software and is no long considered to be just a technical tool. It is considered to be the symbol of modern communications and has constructed a new social relationship. Various implementations of IM software have emerged; for example, QQ, MSN, Yahoo Messenger, AOL Instant Messenger, etc. With the development of such applications, today's IM products form a comprehensive network communication tool.
IM is quite similar to a telephone service, but the telephone performs communication through human voice while IM performs communication based on texts. However, with the constantly-changing user demand, IM can provide more diversified services and be applied to a wider range of areas. The users are not satisfied with merely text communication via IM software. They also desire to share files through IM.
Nevertheless, it is not easy to share files with current IM software. Two scenarios are explained as follows.
Scenario 1
Suppose User A has a lot of music files and he wants to share them with User B, but User B only needs part of the music of User A instead of all the music. In this situation, a conventional process of the current IM software is:                User A chats with User B and tells User B all the music files he has;        User B goes through all User A's files and tells User A which ones he needs; and        User A sends User B the needed music files to realize the “share” object.        
This sharing can be realized using the following ways:                1) “File Send” function: most IM software support this function;        2) “File Share” function: a few IM software applications (e.g., AIM) support this function but can only share the specified folders;        3) as Email attachment;        4) if in LAN, using the file share function of Windows.        
Scenario 2
Suppose User A has a lot of music files and he wants to share some of the music files with User B and share others with User, C, but User B and User C are placed in different groups of User A's contact list (or buddy list).
If the IM software (e.g., AIM) which supports the “File Share” function is used, the user first needs to designate a folder for sharing with others and copy into the folder a file for sharing with User B. Then, User A sets the authority of User B's group to have access to the shared folder so that User B can access the shared folder and obtain the file. After User B gets the needed file, User A deletes all the files from the shared folder. Then User A copies the files which he wants to share with User C into the folder and sets the authority of User C's group to have access to the shared folder so that User C can access the shared folder and get the file.
It can be seen that, in both Scenarios, it is impossible to realize automatic and flexible file sharing between IM software users. Manual operations and intervention are needed instead.
In U.S. patent application US2004/0199514A1, entitled “Techniques for Facilitating Item Sharing” and granted to I. Rosenblatt et al. on Oct. 7, 2004, a technical solution for file sharing through IM software is described. The “File Share” function in item 2) of Scenario 1 and the case of Scenario 2 are similar to the solution presented in this patent. In this patent, a share window is used to maintain a list of shared files/folders, and a user can add files/folders for sharing with others to the share window, and other users can only access the files and folders listed in the share window.
Moreover, U.S. patent application US2004068524, entitled “Peer-to-peer File Sharing”, and granted to A. Amir et al. on Apr. 8, 2004, discloses a shared folder is established among a plurality of users and the content of the folder is shard among these users. The files in the shared folder may exist in computers of different users. However, this patent does not particularly concern file sharing through IM software, and needs to establish a virtual file to realize sharing.
It can be seen that, a workable solution capable of performing file/folder sharing between IM software users is needed.